[adamzerner]

Yeah, I have learned a few things from the comments here and my understanding isn't perfect. Previously I thought of `n` as arbitrary; that it can be whatever you define it to be. I see now that you're right that technically it has a more precise definition: it refers to the input size.

However, I also think that in _practice_, as Znafon [says](https://news.ycombinator.com/item?id=24661411), the meaning of `n` is clear and it makes sense to stretch the technical definition a bit. In my experience, people often do. Imagine if there were one trillion vowels. It wouldn't be practical to describe it as an O(1) algorithm, despite what the answers to exam questions might say.

That said, I think that it is worth understanding the distinction between what `n` means in theory vs practice, so I was going to add a note to the blog post in order to avoid confusing readers, like you recommend. However, as I tried to do so, things got too side-tracked. Too many tangents, especially ones that aren't the easiest to understand, makes the post harder to follow. So I decided on linking to this thread parenthetically. That seems to my eye to strike the right balance.